The present invention relates to a screw feeding device and more articularly, to a feeding device that has a compact size and includes an adjusting shaft for the safety board so that the device is easily to be assembled, operated and the depth of the screws can be controlled.
A conventional screw feeding device known to the applicant is disclosed in U.S. Pat. No. 5,402,695 to Hornung and shown in FIGS. 1 to 4. The device includes a guide body 10 and a barrel 11 which is connected to the guide body 10 by a spring and includes a shaft 12 pivotably received therein. An end of the shaft 12 has an axle 14 for connecting two gears 13 and the other end of the shaft 12 is movably received in a slot 101 in the guide body 10. A positioning member 16 with a spring 15 are connected to the front end of the barrel 11. The shaft 12 swings in the slot 102 so as to let the two gears 13 drive the belt 18 with the screws 17. Notches 131 are defined in an inner side of each gear 13 and a one-direction valve 133 with a spring 132 are located between the two gears 13 so that the gears 13 can only rotate in one direction by the valve 133. The belt 18 and the screws 17 move in the direction and the positioning member 16 positions the belt 18.
Due to the movement of the two gears 13 is made by the swinging of the shaft 12, and the two gears 13 have to cooperate with the valve 133 and the positioning member 16 so that the whole assembly is complicated and involves too many parts. It requires complicated manufacturing processes to make the notches 131 in the two gears 13 and to install the spring 132 in the one-direction valve 133. The whole assembly occupies a lot of space. The belt 18 is not conveniently positioned because it is engaged with two gears 13. Furthermore, the cooperation between the swinging of the gears 13 and the positioning member 16 cannot be satisfied by the users.
The primary object of the present invention is to provide a screw feeding device that has a compact size and is easily to be assembled. A gear, a positioning gear and a hollow shaft are made into a one piece member and a one-direction bearing is received in the hollow shaft, a biasing plate is engaged with the positioning gear, thereby simplifying the structure of the device and may have a compact screw feeding device.
Another object of the present invention is that the screw feeding device may adjust the depth of the screws. An adjusting shaft is cooperated with a safety board, the adjusting shaft has an inclined surface which is engaged with a bead so as to be positioned precisely to achieve the purpose of micro-adjusting the depth of the screws.